Monthly Archives: November 2014

It is supposed to make the surface below a radiatively active atmosphere warmer than if this particular kind of atmosphere weren’t there. By extension, one could claim – and this is after all what the ‘Anthropogenic Global Warming hypothesis’ is all about – that the stronger the rGHE, the stronger its warming effect.

Now, as far as I’m concerned, this is a prediction that should be possible to test. Or else, what good is it?

Again, what is the strictest definition of the rGHE? What is its ‘surface warming mechanism’ supposed to be, in the simplest of terms? We went through this in Part 1, where what was defined as the “greenhouse effect” of clouds was overwhelmed by their opposing “albedo effect”, leading to an overall – net – cooling effect.

It is found simply and solely in the reduction in outgoing radiative (LWIR) flux from the surface to the top of the atmosphere (ToA) – the surface flux minus the ToA flux. (The surface flux is calculated directly from the surface temperature (based on a blackbody assumption, through the Stefan-Boltzmann equation), while the ToA flux is rather estimated from actual measurements made by satellite-borne instruments.)

This turned out to be a longer post (the first of two) than what I had originally planned. The actual presentation and analysis of data starts only about halfway through. If you don’t much care for my ranting about how ‘the climate establishment’ deliberately employ specious arguments and methods to try and make us believe and perceive that clouds somehow massively warm the Earth even when they’re not, then please feel free to scroll past the first three or four sections.

THE NEGATIVE “CLOUD GREENHOUSE EFFECT”

Yes, we have all experienced how clouds covering the sky on a sunny day will tend to cool things down. Heck, shade or sunshine, which is hotter? Likewise, I think most of us can attest to the experience of how a cloudy night will be milder than a clear one.

These two different ‘cloud effects’ work in opposite directions. During the day, the heat comes in from the Sun: Qin. If you then pull a blanket or something similar between you and the heat source, you will (hopefully) avoid being overheated. People living in deserts know all about this principle. They wear their long, loose, bright garments not to stay warm, but in order to stay cool. Note, there is also heat going out (from the surface) during the day (Qout) – a direct consequence of the original solar heat input. But in most cases, this is totally overwhelmed by the incoming solar heat, so much so that it’s normally forgotten about, unless you happen to step onto a hot pavement or sand. Since the outgoing heat is also very much dependent on the original solar heating, reducing Qin during the day would also necessarily reduce Qout.

During the night, there is no more heat coming in from the Sun. There is only the heat going out, at this point from excess solar energy having accumulated during the day. So the surface is no longer being heated. Its temperature is dropping. It loses energy (as heat). Cooling. It cools directly to space, but also substantially to the air/atmosphere above it, which then in turn cools to space from higher up on its behalf, so to say. What happens if we now pull a blanket over the scene? Well, the remaining heat source, the ground, is now obstructed from direct access to its ultimate cold reservoir, space. The heat being expelled is to a much lesser degree able to go straight to the outer, icy cold heat sink, it goes rather to the more warmish layer in between. Reducing the overall gradient, thus reducing the cooling rate. People living in cold places know all about this principle. They wear thick, heavy, fluffy clothes in multiple layers, not to stay cool, but to stay warm.

The wonders of insulation! It works both ways. You only need to figure out where the principal heat is coming from.

OK, so this should be our starting point: Clouds exert both an indirect ‘cooling’ and an indirect ‘warming’ influence on surface temperatures. They take away from the solar input during the day (>Qin), and they reduce the ground’s cooling rate during the night (>Qout).

So which of these contrary ‘cloud effects’ is stronger?

Well, the heading above should give you an inkling of sorts. But I fear we will have to wind our way forward a bit before reaching final enlightenment.